Artificial perfect electric conductor-perfect magnetic conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency
Artificial perfect electric conductor-perfect magnetic conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency
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DOI：
10.1063/1.4941696
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发表时间：
2016-02-14
影响因子：
3.2
通讯作者：
Sha, Wei E. I.
中科院分区：
文献类型：
--
作者：
Chen, Menglin L. N.;Jiang, Li Jun;Sha, Wei E. I.
轨道角动量（OAM）是电磁学和量子力学基础研究中一个很有前途的自由度。OAM具有无限的状态空间，在增强经典和量子通信信道容量方面具有巨大的潜力。通过探索Pancharatnam-Berry相位概念和在具有空间变化取向的超颖表面中设计各向异性散射体，具有零OAM的平面波可以转换为携带非零OAM的涡旋光束。本文提出了两种新型的理想电导体--理想磁导体各向异性超颖表面。一个是由方位连续的环路，另一个是由方位不连续的偶极子散射体。两种类型的超颖表面都安装在蘑菇型高阻抗表面上。与先前用于生成OAM的元表面设计相比，所提出的元表面设计实现了近乎完美的转换效率。考虑到电场的垂直分量被消除，连续超颖表面在近场区域显示出非常平滑的相位图案，这是由离散散射体组成的对流超颖表面所不能实现的。另一方面，具有离散偶极散射体的超颖表面显示出极大的灵活性以产生具有任意拓扑电荷的OAM。我们的工作对高性能OAM生成具有根本性和实际意义。(C)2016 AIP Publishing LLC.
Orbital angular momentum (OAM) is a promising degree of freedom for fundamental studies in electromagnetics and quantum mechanics. The unlimited state space of OAM shows a great potential to enhance channel capacities of classical and quantum communications. By exploring the Pancharatnam-Berry phase concept and engineering anisotropic scatterers in a metasurface with spatially varying orientations, a plane wave with zero OAM can be converted to a vortex beam carrying nonzero OAM. In this paper, we proposed two types of novel perfect electric conductor-perfect magnetic conductor anisotropic metasurfaces. One is composed of azimuthally continuous loops and the other is constructed by azimuthally discontinuous dipole scatterers. Both types of metasurfaces are mounted on a mushroom-type high impedance surface. Compared to previous metasurface designs for generating OAM, the proposed ones achieve nearly perfect conversion efficiency. In view of the eliminated vertical component of electric field, the continuous metasurface shows very smooth phase pattern at the near-field region, which cannot be achieved by convectional metasurfaces composed of discrete scatterers. On the other hand, the metasurface with discrete dipole scatterers shows a great flexibility to generate OAM with arbitrary topological charges. Our work is fundamentally and practically important to high-performance OAM generation. (C) 2016 AIP Publishing LLC.